Conventional bricks or blocks have long been used to construct, for example, walls as disclosed in U.S. Pat. No. 3,894,397 (Fair), the disclosure of which is hereby incorporated by reference. However, several limitations and disadvantages have been associated with the use of such construction units, principally of which has been the need for the use of mortar between the blocks or mechanical fasteners to provide stability. In addition, they could not readily be utilized to form diagonal structures. However, the disadvantages and limitations associated with such construction units are more readily recognized in regard to sound barrier walls or privacy fences, which heretofore could not easily be constructed with voids, indentations and extrusions produced within the wall face that could absorb or reflect noise. An example of such would be highway sound barriers and retainer embankments which are either of wood, concrete blocks or precast segments of concrete lowered in place and retained along their ends by supports. Such concrete blocks have included generally T-shaped blocks as disclosed, for example, in U.S. Pat. No. 3,282,052 (Saginor), the disclosure of which is hereby incorporated by reference. In addition to the previously mentioned limitations, the precast segments require staggering of sections as the only means by which to provide some aesthetic features to the walls.
Also, structures constructed in accordance with the above do not provide sufficient permeability for use in present day landscaping, and do not provide sufficient expansion and contraction. However, blocks have been suggested for breakwaters as disclosed, for example, in U.S. Pat. No. 2,474,786 (Humphrey) and for granaries as disclosed, for example, in U.S. Pat. No. 1,277,829 (Baum), the disclosures of which are both hereby incorporated by reference.
Thus, there has been a need for an intermeshable construction unit which would not require mortar for interlocking, yet provide durability, economy, appearance, utility and good acoustics. In addition, such an intermeshable construction unit should be capable of being used to create symmetrical or random designs featuring voids, indentations and extrusions within a wall space that can baffle, absorb or reflect noise. Also, the intermeshable construction units should be able to mesh with one another to allow the structure to flex during periods of expansion and contraction. Further, structural strength should be able to be increased by zig-zagging or curving the vertical wall plane of a structure. Lastly, when intermeshable construction units are constructed in a diagonal plane, they should be able to armor, retain or change the angle of repose of a natural embankment.